Coffin-Siris syndrome: a case report

*Correspondence: [e-mail].

Abstract

Case Presentation: An infant male, born full-term via cesarean section, with an Apgar score of 9/10 and a weight of 2400g. At 11 months, he exhibited social smiling, head control, and vocalizations, but he did not sit with support or speak, and a global delay in development was suspected. Physical examination revealed brachycephaly, preserved strength in the limbs, axial, gluteal, and limb hypotrophy, limb length discrepancy, thickened fingers and toes, prominent abdominal wall, and anteverted nostrils. Magnetic resonance imaging of the brain showed partial agenesis of the corpus callosum and prominence of extra-axial cerebrospinal fluid spaces in the frontotemporal regions. Genetic evaluation at 12 months of age revealed brachycephaly, long eyelashes, a long and mildly pronounced nasolabial filter, low hair implantation on the forehead, hirsutism, increased space between the first and second toes, prominent hallux, and hypoplasia of the distal phalanx of the fifth finger of the left hand. Peripheral blood karyotype was normal (46 XY), and microarray analysis showed a microdeletion on the long arm of chromosome 6 (6q25.3), corresponding to the interstitial region containing the ARID1B gene associated with Coffin-Siris syndrome. Currently, at 2 years of age, the patient still exhibits delay in neuropsychomotor development. He cannot speak or walk and sits with support. He is receiving physical, occupational, and speech therapy.

Discussion: Coffin-Siris syndrome is a rare disorder, with less than 300 confirmed cases identified through molecular testing to date. It is characterized by hypoplasia or aplasia of the distal phalanx or nail of the fifth finger, delayed neurodevelopment, distinctive facial features, hirsutism, hypotonia, and sparse hair on the scalp. One of the main genes associated with the syndrome is ARID1B, whose mutation, usually resulting from a de novo event, impairs the process of chromatin remodeling in the body. In severely affected children, the prognosis is poor, and they may die due to aspiration pneumonia or seizures. Therefore, when presented with a suggestive clinical picture, genetic investigation should be carried out in order to establish a diagnosis and prompt multidisciplinary management.

Final Comments: Coffin-Siris syndrome can result from mutations in various genes, with ARID1B being the most frequent, leading to a multisystemic clinical picture that, if diagnosed early, has a beneficial prognostic impact.

Publication History

Article published online:
12 May 2025